The Autopsy

Autopsy authorization

The Medical Examiner is authorized by statute to perform an autopsy on any body within his/her jurisdiction, and therefore does not need further consent.

Medical autopsies may be performed in any case where authorization has been given by a member of one of the following classes of persons in the following order of priority:     (1) The surviving spouse or state registered domestic partner;     (2) Any child of the decedent who is eighteen years of age or older;     (3) One of the parents of the decedent;     (4) Any adult brother or sister of the decedent;     (5) A person who was guardian of the decedent at the time of death;     (6) Any other person or agency authorized or under an obligation to dispose of the    remains of the decedent.

CAP recommends keeping wet tissue from forensic autopsies for 1 year

- for hospital autopsies, CAP recommends keeping tissue for 3 months

Electrolyte levels in decomposition

Postmortem vitreous potassium levels has been attempted to help determine the time of death but methods have been found to be invalid

Anything that accelerates decomposition, increases the level of vitreous potassium

Decomposition = Increased K+, Decreased Na+, Cl-, and Glu

Therefore if Na, Cl, or Glucose levels are high they are more significant than low values

Link to detailed chart of vitreous findings in different conditions:

http://emedicine.medscape.com/article/1966150-overview#aw2aab6b4

Rigor Mortis

“Stiffening” of the body after death due to postmortem muscle contraction. Begins in first in smaller muscles (fingers, jaw) then progresses to the limbs

Due to depletion of ATP with resultant development of a stable complex of actin and myosin , thus preventing muscles from relaxing

Maximal onset between 6-12 hours postmortem

Rigor mortis comes on much more quickly if decedent was exerting themselves before death (eg. drownings)

Persists for 36-48 hours (less in hot weather; longer in cold weather)

Autolysis

- the breakdown of one's self by one's self; the aseptic breakdown of tissue

- maceration: "pure" autolysis in stillborn fetus; bc no bugs are yet in baby's gut, little to no putrefaction occurs; looks like a burn, does not smell

- sepsis, insects, and high ambient temperature speed up tissue breakdown; where low temps slow it down

- determining cause of death in decomposed body can be difficult/impossible (must distinguish pre-/postmortem injuries, look for tool marks, do x-rays, toxicology, other lab tests)

Putrefaction - breakdown of tissue by bacteria, usually in large bowel

- almost always starts as a little green patch in right lower abd

- later can see linear red discolorations as bacteria invade BVs

-- "marbling" caused by breakdown of BVs, at which point not possible to get blood sample

Skeletonization

Mummification - decomposition in very dry envt

- embalming can also preserve tissue c chemicals

Burns

At 120 F, exposure for 5 min can cause 3rd degree burns

- at 150 F, will get 3rd degree burns after 2 seconds